Modular steering wheel assembly with integrated switch housing

ABSTRACT

An improved steering wheel assembly includes an integrated switch housing that includes the stalk switch for the vehicle, and further provides the fixed housing for a clock spring. The integrated switch housing reduces the overall size and length of the switches adjacent the steering wheel. Moreover, the integrated switch housing is preferably used with a modular steering wheel and air bag combination that is attached to the wheel after pre-assembly of the modular units. Locking structure ensures there is no relative rotation between the clock spring rotating plate, the clock spring fixed housing, and the modular steering wheel combination until the entire assembly is mounted to the steering column. The combined integrated modular assembly allows testing of all electrical connections prior to mounting the combined assembly to the vehicle.

BACKGROUND OF THE INVENTION

This invention relates to an assembly which attaches a steering wheel,and electrical switches and connections on and adjacent the steeringwheel, to the steering column as a modular unit.

In the prior art, the assembly of the steering wheel is typically amulti-step process. Initially, the electrical connections between thesteering column and a clock spring are made. A clock spring is a knownelectrical connector which allows relative rotation between electricalcomponents on the steering wheel (such as the air bag, horn, cruisecontrol, etc.) and the electric connections leading to systems orcontrols on the vehicle. A clock spring typically allows severalrotations of the steering wheel in either direction while maintainingelectrical communications between the steering wheel mounted elementsand the fixed steering column.

In the prior art, the clock spring is typically attached to structure onthe steering wheel to complete the electrical connections. Moreover,switches mounted on the steering column, such as stalk switches, mustalso be attached prior to attachment of the steering wheel. Typically,the switches are mounted in a separate housing that must be mounted onthe steering column. Once the housings are mounted, the steering wheelis attached to the wheel column. The air bag is then attached to thesteering wheel. A cover for the air bag is then placed over the air bag.Typically, an ignition switch is cast into the steering column. Thefirst time an operator may fully test all electrical connections andswitches associated with the steering wheel is only after the componentshave been assembled onto the vehicle. If a problem is discovered, theassembler must then remove the assembly from the vehicle for repair.

The above-described assembly is relatively time-consuming, and laborintensive. Moreover, it requires the final vehicle assembly location toperform a high number of assembly steps. Further, it limits the order inwhich assembly steps can be performed, and requires the automobileassembly location to maintain an inventory of several different parts.In addition, all of the separate parts and housings increase the overallsize of the assembly.

It is a goal of the automotive industry to reduce the number of partsthat must be assembled as separate pieces, the required size for thecomponents, and the labor required for assembly. Moreover, it is a goalof any assembly application to reduce restrictions on the order ofassembly steps. Finally, it is a goal of the automotive industry toremove as much assembly function from the final vehicle assembly line aspossible.

SUMMARY OF THE INVENTION

In the disclosed embodiment of this invention, an integrated housingmounts a stalk switch adjacent to the steering wheel, and further mountsa clock spring for communicating electrical signals to and from thesteering wheel within a single housing. The integrated housing ispreferably mounted on a modular steering wheel and air bag combination.The combined housing and modular unit will be referred to as anintegrated modular steering wheel assembly for purposes of thisapplication. The entire integrated modular steering wheel assembly maybe mounted to the fixed steering column as a one-piece unit. Thus, thereis not a high degree of labor required at the final vehicle assemblyline.

In further features of this invention, the integrated housing may alsomount an ignition key lock. The key is preferably of the sort having ananti-drive feature until a magnetic member "recognizes" the key. Byintegrating all of the switches into a single housing, the inventionreduces the required size of the assembly.

The integrated modular steering wheel assembly, with all associatedswitches and connections may be preassembled, and tested before beingmounted on the vehicle. As an example, the integrated modular steeringwheel assembly may be preassembled by a component manufacturer, who maythen fully test all switches and electrical connections to and from thesteering wheel on a test jig. In the past, such complete testing couldnot occur until the wheel and its associated components were attached tothe steering column. In the prior art, repairing an electrical problemrequired the wheel assembly to be disassembled. This feature may also beutilized with a modular switch housing assembly including separate stalkswitch and clock spring housings that are assembled together.

In a separate feature of this invention, a structure is provided forattaching the integrated housing to a hub associated with the modularsteering wheel and air bag combination. The modular steering wheel andair bag combination is provided with a driving structure that allows themodular combination to be attached to the vehicle steering column afterhaving been preassembled as a modular unit. The present invention allowsthe attachment of the integrated housing to the modular combination, andstill allows the assembly of the combined integrated modular steeringwheel assembly to the steering column. In one embodiment, a worm gear isaccessible from outside of the modular unit, and is driven to drive agear formed with a nut onto the steering column.

The steering wheel hub is preferably formed with bosses or studsextending from a rear face towards the integrated housing. The studs arealigned in mating structure on the rotating clock spring plate. Therotating plate thus rotates with the hub. A fixed clock spring housingwhich surrounds the rotating plate includes a plurality of openings. Themating structure on the hub and the rotating plate includescomplementary apertures aligned with the openings in the fixed housing.A pin is inserted through the fixed housing openings, and extendsthrough the complementary apertures in the mating structure in therotating plate and hub. In this way, the fixed housing and the rotatingplate are prevented from rotating relative to each other during shipmentof the clock spring, the integrated housing, or of the combined modularunit. In a preferred embodiment of the invention, the integrated housingprovides the fixed housing for the clock spring.

Once the integrated modular steering wheel assembly is placed on thesteering column, the pin may be removed. The rotating plate stillrotates with the hub due to the mating structure. At the same time, therotating plate and hub are now free to rotate relative to the integratedhousing or fixed clock spring housing.

In yet another feature of this invention, the rotating plate carries apivoting latch. One end of the latch extends into the mating structureon the rotating plate. The other end of the pivoting latch extends intoa notch in the fixed housing. When the pivoting lever is received in thenotch, it prevents relative rotation of the rotating plate and theintegrated housing. This prevents rotation of the two members prior tothe attachment of the integrated housing to the hub. It is preferablethat the rotating plate remain at a predetermined rotational positionrelative to the fixed housing prior to being attached to the hub. If therotating plate is at a overly rotated position relative to the fixedhousing when attached, there may be insufficient turning capability inone direction. That is, a clock spring essentially allows a set numberof rotations of the steering wheel relative to the steering column inboth directions. It allows such rotation by rotating the plate relativeto the fixed housing, and compensating for relative movement by a ribboncoil. If the rotating plate is overly rotated relative to the fixedhousing when attached to the hub, then there may be insufficientrotation available in one direction. The latch portion of this inventionaddresses this possibility.

When the hub is mounted to the rotating plate, the mating structure onthe hub force one end of the latch in a sleeve on the rotating plate.This pivots the opposed end of the latch out of the notch, and allowsthe plate to rotate relative to the fixed housing.

These and other features of the present invention can be understood fromthe following specification and drawings, of which the following is abrief description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an exploded view of the three main components of an inventivesteering wheel.

FIG. 1b shows two of the components preassembled as an integratedmodular unit.

FIG. 1C shows an alternative embodiment.

FIG. 2 is an exploded view of the one of the components shown in FIG.1A.

FIG. 3A shows an end view of another of the components.

FIG. 3B is a cross-section of a portion of the FIG. 3A component.

FIG. 4 is a view of an intermediate assembly according to the presentinvention.

FIG. 5 is a view through a portion of the structure shown in FIG. 4.

FIG. 6 is an end view of one portion of the present invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

FIG. 1A shows an assembly 20 incorporating an outer cover 22 surroundinga steering column 24. An integrated housing 26 includes a switch housing28, and a fixed clock spring housing 30 formed integrally with thehousing 28. An electrical connection between the integrated housing 26and the steering column is shown schematically at 27. In practice, theconnections may be more complicated then the simple plugs 27A and 27B.Plug 27B is shown as a schematic representation of all electricalconnections from housing 26, including those from unit 35 as describedbelow.

A rotating clock spring plate 32 is received within fixed housing 30.Plate 32 is formed with a plurality of sleeves 33 that extend towards amodular steering wheel and air bag combination 35. A plurality of studs34 extend from a rear face of the modular combination 35, to mate withsleeves 33. The modular combination 35 includes steering rim portion 36and a rear hub portion 38. The details of this structure are disclosedin a co-pending U.S. patent application Ser. No. 08/547,493, entitled"Modular Steering Wheel and Air Bag Combination".

Pin 40 extends through holes in the housing 30, the sleeves 33 and thestuds 34 to hold the plate 32, the housing 30, and the modularcombination 35 at a desired rotational position. One main feature ofthis invention is the ability to assemble the switches, the steeringwheel, and the air bag as a single integrated modular assembly andattach the entire assembly to the steering column as a one-piece unit.This greatly reduces the number of separate parts, the laborrequirements at the assembly line, and frees up many assembly options.

As shown in FIG. 1B, the integrated housing 26 and the modularcombination 35 have been preassembled into an integrated modularassembly. Pin 40 extends through housing 30, sleeves 34 and studs 34.The pin holds all three of the members together without allowingrelative rotation. It is important to prevent relative rotation of theplate 32 relative to the housing 30 until the entire assembly isattached to the vehicle. An electrical connection 41 is shownschematically, and connects the clock spring to components in themodular combination 35.

One other important aspect of this invention is that once the integratedhousing 26 and the modular unit 35 are assembled as a unit as shown inFIG. 1B, all of the switches and electrical connections on thepreassembled unit may be tested on a test jig prior to being mounted tothe vehicle. The test jig is shown schematically in FIG. 1B connected tothe connection 27B. The structure of the test jig would vary with theparticular electrical connections and switches on the combined housings26 and 35. It is an important aspect of this invention, however, thatthe integrated housing 26 and the modular combination 35 may bepreassembled and fully tested prior to mounting on a vehicle.

FIG. 1C shows a switch assembly including a separate stalk switchhousing 28, and clock spring housing 30. The separate housings can beassembled together to achieve the combined assembly of FIG. 1B fortesting and assembly as a single combined assembly. Known connectionstructure may be used. In fact, in achieving the pretest features ofthis invention many possible combinations and types of switch housingare possible.

As shown in FIG. 2, the integrated housing 26 includes a stalk switch 42included into the integrated housing 26 at switch portion 28. Further,the key lock for key 44 may also be incorporated into the integratedhousing 26. Thus, when the modular unit as shown in FIG. 1B is tested,the stalk switch functions (which typically include windshield wipers,lights, etc.), as well as the ignition function may all be pretestedprior to being mounted on the vehicle.

As can be seen, a foward face 31 of integrated housing 26 has the stalkswitch 42 mounted on one side, and includes a bore 43 for passage of thesteering wheel column. The fixed housing 30 extends from the forwardface 31 in an opposed direction from that of which the stalk switch 42is spaced.

As further shown in FIG. 2, notches 46 are formed in fixed housing 30.The clock spring ribbon 47 is shown schematically, and forms no portionof this invention. A rotating plate 32 includes a plurality of sleeves33. One sleeve 48 has notch 50. A pivot point 52 is formed on plate 30.A pivot latch 54 is mounted at point 52, as will be described below.

As shown in FIG. 3A, the hub 38 of the modular combination 35 includesstuds 34 each having holes 34H for receiving the pin 40. Further, adrive housing 56 includes an access opening 58. A nut 60 is shownextending outwardly of the drive housing 56.

As disclosed in more detail in the above-referenced application, onedrive assembly for attaching the modular unit 35 to the steering column24 includes a worm and worm gear combination. The same drive may attachthe integrated housing 26 as part of this invention.

FIG. 3B shows details of the drive assembly. The worm 62 is driven by atool through the access opening 58. Worm 62 rotates worm gear 64, to inturn drive nut 66 onto threads on the steering column 24. A wedgeconnection is also made between hub collar 68 and the steering column atthat time. Thus, the invention may be preassembled as shown in FIG. 1B,and as long as access is still allowed to the opening 58, the entireintegrated modular assembly may be assembled to a steering column as asingle step. This greatly reduces the required labor.

As shown in FIG. 4, the integrated housing 26 may also be preassembledas a modular unit prior to being attached to the modular combination 35.Sleeves 33 all include holes 33H. The fixed housing 30 includes housingholes 30H. Pin 40 extends through housing holes 30H, and through thesleeve holes 33H. When in the position shown in FIG. 1B, the pin 40 alsoextends through 34H.

As shown in FIG. 4, latch 54 has inner end 71 received in the opening50, and an outer end 72 received in notch 46. Thus, latch 54 preventsrelative rotation of plate 32 and housing 30, even without pin 40. Pin40 also prevents relative rotation of the two until the entire assemblyis mounted on the steering column.

As shown in FIG. 5, once the modular combination 35 is attached to theintegrated housing 26, latch 54 no longer performs an anti-rotationfunction. Instead, stud 34 hits inner end 71 of latch 54 and pivotsouter end 72 outwardly of the notch 46. Latch 54 pivots about a pivotpoint 74 on mount 52. Preferably, a spring is disposed at the pivotpoint 74 to bias latch 54 to the position shown in phantom at 76 in FIG.5. In that position, outer end 72 is received in notch 46. The latchthus prevents relative rotation of plate 32 relative to housing 30 untilthe hub plate is attached to the integrated housing 26.

As shown in FIG. 6, integrated housing 26 may also incorporate theignition switch 44. In this embodiment, an anti-drive control 80initially identifies the key before allowing ignition. This ignition maybe performed electronically, once the control 80 recognizes the key 44.The technology for identifying the key 44 by the control 80 is known,and forms no portion of this invention. It is the incorporation of theignition key function into the integrated housing 26 which is theinventive aspect of this invention.

In completing the assembly of the integrated modular steering wheelassembly to a vehicle steering column, the modular steering wheel andairbag combination is assembled, and the integrated housing is initiallyassembled. The integrated housing sub-assembly includes the steps ofmounting a stalk switch in the integrated housing, and further mountinga clock spring in the integrated housing. The pin 40 may secure therotating plate relative to the fixed housing after this sub-assembly.Alternatively, the latch 54 prevents relative rotation of the rotatingplate and fixed housing. The integrated housing 26 may also mount theignition key, and if so, this is also mounted into the integratedhousing at this point. The integrated housing is then mounted to themodular combination of the steering wheel and air bag. If the separatehousings of FIG. 1C are used they are both attached at this point. Atthis point, the connections 41 between the integrated housing and themodular combination are made. The integrated modular assembly may thenbe tested. At that time, the stalk switch, the ignition key, the clockspring, and all electrical connections in the switch housing or modularcombination may be tested, prior to any of the components being mountedto the vehicle. If a problem or fault is found in any of the electricalcomponents, repair or replacement of that component is much simpler thanif the assembly had already been mounted to a vehicle.

Once the integrated modular assembly has been tested, the entireassembly may be mounted to a vehicle as a single assembly. Structure onthe integrated housing preferably snaps onto steering column 24, or isotherwise connected. The pin 40 is then removed. The worm gear is thendriven to drive the nut onto the threads on the steering column 24. Asthe worm drives the nut 60 onto the steering column, the modularcombination 35 and plate 32 moves downwardly relative to housing 26, andonto the column locking the entire assembly to the vehicle steeringcolumn. This is a simple assembly that greatly reduces the laborrequirements of prior art assemblies. An outer cover may also beincorporated into the assembly to cover the components. Preferably, theouter cover will still allow access to the hole 58 for driving the worm.

A preferred embodiment of this invention has been disclosed, however, aworker of ordinary skill in the art would recognize that certainmodifications would come within the scope of this invention. For thatreason the following claims should be studied to determine the truescope and content of this invention.

We claim:
 1. A modular steering wheel assembly comprising:a steeringwheel rim attached to a hub, and an air bag attached to said hub to forma subassembly; a clock spring including a fixed housing and a rotatingplate attached to said hub for communicating electrical signals to andfrom said subassembly, said clock spring and said subassembly forming anassembly; structure for preventing relative rotation between said fixedhousing and said rotating plate; a drive to attach said assembly to asteering column as a unit, and said structure allowing relative rotationof said fixed housing and said rotating plate after said assembly isattached to a steering column; and said structure including a pin whichextends through at least one opening in each of said fixed housing, saidrotating plate and said hub subassembly.
 2. An assembly as recited inclaim 1, wherein at least one hole is formed in said fixed housing, andsaid rotating plate is formed with a plurality of members which interactwith mating members on said hub to prevent relative rotation of saidplate and said hub, said mating members on said hub and said rotatingplate also being formed with at least one hole such that said pinextends through said hole in said housing, and through said holes insaid mating members.
 3. An assembly as recited in claim 2, wherein saidpin is relatively U-shaped and extends through four of said holes insaid fixed housing, and through at least two of said holes in saidmating members on said rotating plate and said hub.
 4. An assembly asrecited in claim 1, wherein said rotating plate further includes a latchwhich is normally pivoted into a notch in said fixed housing to preventrelative rotation of said rotating plate relative to said fixed housing,said lever pivoting out of said notch when said clock spring is attachedto said subassembly.
 5. A modular steering wheel assembly comprising;asteering wheel rim attached to a hub, and an air bag attached to saidhub to form a subassembly; a clock spring including a fixed housing anda rotating plate attached to said hub for communicating electricalsignals to and from said subassembly, said clock spring and saidsubassembly forming an assembly; structure for preventing relativerotation between said fixed housing and said rotating plate; a drive toattach said assembly to a steering column as a unit, and said structureallowing relative rotation of said fixed housing and said rotating plateafter said assembly is attached to a steering column; said rotatingplate further including a latch which is normally pivoted into a notchin said fixed housing to prevent relative rotation of said rotatingplate relative to said fixed housing, said lever pivoting out of saidnotch when said clock spring is attached to said subassembly; and saidrotating plate includes a plurality of hollow sleeves, and said hubincludes studs which extend into said hollow sleeves, said latch havingone end received in one of said sleeves, one of said studs contactingsaid latch and pivoting said latch out of said notch when said hub isattached to said clock spring.
 6. An assembly as recited in claim 5,wherein said hub is attached to said clock spring prior to beingattached to a vehicle.
 7. An integrated switch housing assemblycomprising:a one-piece housing mounting a switch stalk for providing anoperator with several control options; a clock spring including arotating plate received within said housing, said housing providing thefixed housing for said clock spring; said one-piece housing including aforward face including a central hole for passage of a steering wheelcolumn, said switch stalk being mounted on one side of said forwardface, and said fixed housing of said clock spring extending in theopposed direction from said forward face; and including structure toprevent relative rotation of said plate and said fixed housing duringtransport or assembly or said switch housing, said structure including alatch biased to a locking position in a notch in said fixed housing,said latch fixed to said rotating plate, said latch being moved out ofsaid notch to a non-locking position when said housing is mounted onto asteering wheel assembly, said latch pivoting on said rotating platebetween said locking and non-locking positions, said latch having twoends, and being pivotally attached to said rotating plate at a centrallocation between said two ends, one of said ends extending into a sleeveon said rotating plate, the other of said ends extending into saidnotch, said housing including at least one hole, and a correspondinghole in said sleeve, and a pin extending through said holes to hold saidrotating plate against rotation relative to said housing duringtransport of said switch housing.
 8. A switch housing as recited inclaim 7, wherein said housing further includes an ignition switch.
 9. Aswitch housing as recited in claim 8, wherein said ignition switchincludes an anti-drive means to recognize a key.
 10. A method ofassembling a steering wheel onto a vehicle comprising the steps of:1)providing a steering wheel, a hub for mounting said steering wheel to asteering column, an air bag, and a clock spring for communicatingelectrical connections to and from said steering wheel and said air bag;2) attaching said air bag, said steering wheel and said hub as a firstmodular unit; 3) mounting said clock spring onto said first modularunit; 4) providing structure for preventing relative rotation between afixed housing and a rotating plate in said clock spring, and said hub,said structure for preventing relative rotation including a removablepin extending through holes in said fixed housing, said rotating plateand said hub; 5) mounting said clock spring and said first modular uniton a vehicle as a single assembly; 6) then removing said structure forpreventing relative rotation between said fixed housing and saidrotating plate and said hub.